Some conventional turbo machines, such as gas turbine systems, are utilized to generate electrical power. In general, gas turbine systems include a compressor, one or more combustors, and a turbine. Air may be drawn into a compressor, via its inlet, where the air is compressed by passing through multiple stages of rotating blades and stationary nozzles. The compressed air is directed to the one or more combustors, where fuel is introduced, and a fuel/air mixture is ignited and burned to form combustion products. The combustion products function as the operational fluid of the turbine.
The operational fluid then flows through a fluid flow path that is defined between a plurality of rotating blades and a plurality of stationary nozzles disposed between the rotating blades, such that each set of rotating blades and each corresponding set of stationary nozzles defines a turbine stage. Some turbines used for electrical power generation may have three stages, while others may have four stages. As the plurality of rotating blades rotate the rotor of the gas turbine system, a generator, coupled to the rotor, may generate power from the rotation of the rotor. The rotation of the turbine blades also causes rotation of the compressor blades, which are coupled to the rotor.
Ensuring proper alignment of the gas turbine rotor to the gas turbine casing allows the gas turbine to operate most efficiently, reduces the likelihood of compressor blade tips rubbing on the compressor casing or turbine blades rubbing on the turbine shell, and reduces the likelihood of uneven part wear that may result from uneven air flows through the gas turbine. The alignment process is performed during initial build or installation of the gas turbine and may also be performed during outages in which the gas turbine casing and/or rotor have been moved. The ability to the operator of the gas turbine to correct misalignment and/or undesirable clearances between the rotating compressor or turbine blades and the respective portion of the gas turbine casing ensures operational efficiency and preserves power generation output.
A system is needed for quickly and accurately measuring the eccentricity of the gas turbine casing relative to the rotor at one or more axially spaced stages.